We propose to purchase a peptide synthesizer and two HPLC apparatus. The entire system would enable us to perform the synthetic steps necessary to make polypeptides of 20-50 residues, to analyze the product by HPLC and to carry out large scale purification using preparative HPLC. This system will be part of a protein chemistry facility which is already operating and serving over twenty participating faculty members. Advances in recombinant DNA technology and DNA sequencing have made it possible to deduce the primary structure of proteins from any organism where the DNA can be obtained and the gene of interest identified. The putative protein specified by the gene need not have been isolated or even shown to exist. In the case of procaryotes and viruses, mutations in structural genes specifying proteins of interest, when correlated with a particular phenotype, provide clues as to the function of the protein. The actual demonstration and subsequent isolation of the putative protein can be accomplished if antibodies specific for the protein can be generated. Attempts to raise antibodies using synthetic peptides having sequences identical to these deduced within the desired protein, have been extraordinarily successful. The number of instances where this approach has worked is impressive enough to confidently predict that it will be generally applicable. It is therefore essential that the apparatus and methodology for rapid and efficient peptide synthesis be available to use this approach for a whole variety of significant biological problems where valuable information could be obtained if a protein (whose presence has been inferred solely from genetic data) could be isolated and characterized. This is then the main reason for requesting this equipment and it represents a common theme in many of the projects included here. There is, however, a need in some of the projects for relatively large amounts of certain peptides where specific amino acid residues can be substituted at particular positions so that their effect on complex formation with oligonucleotides or membranes can be evaluated the spectroscopic methods, such as NMR and calorimetry. The peptide synthesizer, as well as the analytical preparative HPLC equipment will make it possible to successfully carry out these projects in a timely fashion.